Water heating system



C. M. OSTERHELD WATER HEATING SYSTEM Filed Nov. 16, 1940 INVENTOR CL AHADam/map BY Whi 35f AT T ORNEY Dec. 16,- 1941.

. pipe l3 at the bottom thereof and a hot water v Patented Dec. 16, 1941UNITED STATES PATENT OFFICE WATER HEATING SYSTEM Clark M. Osterheld,Stougliton, Wis., assignor to McGraw Electric Company, Elgin, 111., acorporation of Delaware Application November 16, 1940, Serial No.365,919

11 Claims. (01. 219-39) My invention relates to electric water heating Iprovide an electric heater 21 which may be systems and particularly toall-day electric water of substantially annular shape extending aroundheating systems. the tank I I and which may be positioned in a An objectof my invention is to provide a relatunnel 23 of any suitable or desiredstructure. tively simple and easily operable. water heating Reference my e e a e o my Patent o. system especially adapted to be used ondomestic 2,226, 26 issued December 24, 1940, for a type hot water tanksthat shall start out the daytime of heating element which may be used,although part of a day with substantially a full tank of my invention isnot to be considered as being hot water and that shall permit ofmaintaining limited thereto. at least a predetermined fractional partoi! the I provide a lower main thermally actuable water content of thetank at a desired relatively switch 25 which; for illustrative purposes,is high temperature. shown as comprising a tubular member 21 whichAnother object of my invention is to provide is shown as connected inthe wall of tank H a hot water heating system that shall be subject t are a ve y low p t e e tubular to remote control of an easily actuatabletype. member 21 to extend into the tank to be sur- Other objects of myinvention will either be rounded by the water near the bottom of theapparent from a description of several forms of tank. The switchincludes also an expansion rod systems embodying my invention or suchobjects 29, a relatively rigid contact bar 3| and a resilwill be setforth in the course or a description lent contact bar 3 norma y y el nelbiased of my systems and particularly in th appended into engagementwith the rigid contact bar 3| claims. but adapted to be moved out ofengagement In the single sheet of drawings, therewith by the expandedrod 29 when the ther- Fig. 1 is a schematic representation f a sys--mally actuable switch is responsive to the tem embodying my inventionshown a applied relatively high temperature of hot water. While to anordinary domestic hot water tank, 25 I have shown specific positions ofthe main ther- Fig. 2 is a view similar to Fig. 1 but showing mallyactuable switch and of the heater, I do not a somewhat different form ofremote control for de to be limited thereto but desire y that thesystem, and. the thermally actuable switch shall be effective Fig. 3 isa further modification of my improved to cause dise e t of c a a 33 fromsystem. contact bar 3| when substantially all of the water In manysmaller urban communities the cenin the tankis tral station supplyingelectric current to its users I Provide further an auxiliary thermally110-- in that community or district may d ir t tuable switch 35 which islocated in a different maintain a supply of electric energy particularlyand P e y pp p 0! the tank and Which for hot water heating during theentire twenty- 35 Comprises 8 bular member 3 an exp four hours of a dayin contrast to the so-called rod 39, 8 relatively rigid Contact bar 4| da oil-peak water heating systems."- The Operation resilient contact bar43 which latter is normally and the results obtained. by the use of myimyieldinsly as d into n a m nt th onta t proved system will be evidentfrom a description 4| but is adapted to be moved, Out Of engagecfseveral forms of control operatively related to. meht therewith when thetubular member 37 S and useable with my improved system. surrounded byhot water. 7

Referring first of all to Fig. 1 of the drawing, While I have shown a peific position or the I have there shown an ordinary hot water tankthermally actuable switch 35 at appr imateh II whi i provided t a coldwater inlet half of the heightv of the tank, I do not desire to belimited thereto and may mount this thert t pipe 15 t t top end thereof 1may mally actuable switch at any desired point in the also provideheat-insulating material I! around tank and Subject it to thetemperature of the the tank and an outer, preferably metal casing Waterat that Point in tank- Generally then, IS in order to hold theheat-insulating material instead of referring o a an alfull of hot inits proper operative position around the tank. Water, I 1188 theexpression a predetermined It is to be understood that whil I h 111fractional part of the water content is hot or trated a specificembodiment of a hot water tank, cold in O der to efer to the re at equantity my invention is not. limited thereto and these of hot or coldwater in the tank. details may be varied, it having been shown more Iprovide an electromagnetic switch 45 which I particularly forillustrative purposes. 7 includes a coil 41, a magnetizable core membercircuit conductor I I.

49, a contact bridging member 5| secured tothe core 49 and a pair ofrelatively fixed contact members 53 engageable with and disengageablefrom the bridging member 5!, all in a manner well-known in the art.

I provide further a second electromagnetic switch 55 which includes acoil 51, a core member 59 having connected therewith acontact bridgingmember 6| and also a pair of fixed contact members 63 adapted to beengaged by bridging member 6|.

One of the fixed contact members 53 is connected by a conductor 65 withone terminal of coil 51, with one of the fixed contact members 63 andwith one terminal of the heater N. The other terminal of heater 2I isconnected by a conductor 61 with contact bar 3i while contact bar 33 isconnected by a conductor E9 to a supply The other fixed contact member53 is connected by a conductor IS with the other supply circuitconductor i5. A conductor 11 connects contact member 53 and theconductor I3 with the other fixed contact member 63. The other terminalof coil 5! is connected by a conductor I9 with contact bar 43 whilecontact bar 4| is connected by a conductor M with contact bar 35 andtherefore with conductor 677.

I have illustrated generally only an electric supply station by thebroken-linerectangular figure t3 and have also illustrated analternating current generator 85 therein in the usual manner, whichgenerator or source of electric current may be of any of the now wellmown kinds, such as a water wheel driven generator, a high speed turbinedriven generator or it may be a rotary converter of the kind used inautomatic electric sub-stations. A means for controlling the supply ofelectric energy from the generator or source 85 is illustrated generallyby a manually actuable switch 8'! and I have further illustrated,generally only, a set of bus bars t9 and 9E which are connected to thesupply circuit and conductors ii and H5 in the usual well known manner.I have shown broken-line connections between the power house ends of thebus bars at and 96 and the supply circuit conductors ii and iii toillustrate that these-two parts are separated by some distance, all inaccord with'the present practice in this art.

I provide further in the generating station 83 a generator 93 which isadapted to generate relatively high frequency alternating current whichmay have a frequency on the order or several thousands alternations persecond, all in a manner well known in the art. One terminal or the highfrequency generator 93, which may be driven by any suitable or desiredsource of power, connected by a conductor to the hue bar 89 andtherefore to the supply circuit conductor ll. I provide a switch 9?which is here shown, for exaniples salre, as a manually actuahle singlecontact switch connected to the other side oi the generator 93 andprovide a conductor 9'3 connect ing this switch to the bus bar 93 andtherefore to the other supply circuit conductor EU.

The coil ll of electromagnetic switch GB is adapted to be energized fromthe high frequency generator 98 upon closure of the switch 9? by anoperator in the central stationor by anyother means which may beconsidered desirable and in order to tune the coil G? to respond to anenergization oi the high frequency current, I connect one terminal ofthe coil ll through a con= ductor Hill to supply circuit conductor ill.The

other terminal of coil 41 is connected by a conductor I03 to oneterminal of, an adjustable condensor I05, the other terminal of which isconnected to one terminal of an adjustable reactance coil I01, the otherterminal of which is connected by a conductor I09 to supply circuitconductor I5. The desired result obtained in the operation of thiscarrier frequency control is that while coil 81 is not responsive to theelectric current of the ordinary frequency of say, 60 cycles, it willrespond by suitable adjustment of the condenser I05 and the reactor I01to the high frequency current when the switch Si is closed.

Let it be assumed that as contemplated in the operation of my improvedwater heating system,

the operator in the power house closed switch 91 at say 12 or 1 oclock,and kept it in closed condition. Under these conditions the energizedcoil as 41 would cause upward movement of core 49 and of the contactbridging member M, which latter would engage the fixed contact members53 and since the conductors I3 and 89 were connected responsively tosupply circuit conductors I5 and ii and therefore to the bus bars 9i and89, an' energizing circuit through the heater 2i would be established asfollows: From supply circuit conductor it, through conductor it, throughthe engaged contact members 5i and 53, through conductor 65, throughheater 2 i, through the engaged contact bars and 33 and from therethrough conductor 659 to the supply circuit conductor 'H which, as aboveset forth, is continuously energized. It is, therefore, evident thatunless the tank 9 I is entirely filled with hot water at the time of thestart of this continued energization of electromagnetic switch 35,current would flow through the heater 25. through the energizing circuitjust above set forth and itis further evident that this energizationwould continue until substantially all of the water in the tank M ishot, which, of course, might occur at any time after energization of theheater having been effected, in accordance with the quantity of hotwater in the tank at the start of this continued energization. Theofi-pealr period as usually understood, is that part of a twenty-fourhour day extending from 10:00 p. m. to 6:00 a. m, or of any otherduration of a time when the ordinary demands for current may berelatively light and since a large part of the load on a central stationdistributing system consists of residence lighting, the oil-peak periodwill usually he found to occur during the later part of the night.

As above stated, deenergization oi? the heater M of any one installationwill occur when all of the water in the tank is hot and it is relativelyeasy for the eng neers of a central station to de= termine, at leastgenerally, when it is desirable for the central station operator tostart the con tinuing closure oi the control element 15 with 2,286,249switch 31 at any desired spaced times of the day will now be described.

Let it be assumed, for more clearly setting forth the operation of mysystem, that at say 10:00 a. m., earlier withdrawals of hot water fromthe tank resulted in the upper auxiliary thermally actuable switch 35being subject to cold water, that is, less than said predeterminedfractional part of the water content of the tank is hot at that time.Momentary closure of switch 91 will close an energizing circuit throughcoil 51 of the electromagnetic switch 55, as follows: From supplycircuit conductor 15 through conductor 13, through engaged contactmembers 53 and through a part of conductor 65, through coil 51, throughconductor 19, through engaged contact bars 43 and 4|, through conductor8|, through engaged contact bars 3| and 33 and from there throughconductor 69 to the other energized supply circuit conductor 1|. Underthe conditions set forth above, that auxiliary switch 35 was subject tocold water, contact bars 43 and 4| would be in engagement with eachother and it is further evident that contact bars 33 and 3| would alsobe in engagement with each other since the lower, main thermallyactuable switch 25 would be subject to cold water if the upper auxiliarythermal switch is subject to cold water.

The energized coil 51 would cause upward movement of core 59 and contactbridging member 6| and a heater energizing circuit would be establishedas follows: From supply circuit conductor 15 through conductors 13 and11, through engaged contact members 63 and 6|, through conductor 65through the heater 2|, through conductor 61, through engaged contactarms 3| and 33 and from there through conductor 69 to the otherenergized supply circuit conductor 1|. At the same time a holdingcircuit for the coil 51 would be established as follows: From supplycircuit conductor 15 through conductors 13 and 11, through engagedcontact members 63 and GI, through coil 51, through conductor 19,through engaged contact bars 43 and 4|, conductor 8|, engaged contactbars 3| and 33 and from there through conductor '69 to the other supplycircuit conductor 1|. It is, therefore, evident that momentary closureof control switch 41 will result in establishing and maintaining aheater energizing circuit in case the amount of hot water in the tank isless than enough to sub- Ject the auxiliary thermal switch 35 to it.This heater energizing circuit, established by momentary application ofany suitable form of electric energy to the control element 41,therefore results in a continuing energization of the heater 2| if lessthan a predetermined fractional part of the water content of the tank ishot, such energization of the heater continuing until the auxiliarythermal switch 35 is subject to water having a predetermined relativelyhigh temperature at which time contact bar 43 will be moved out ofengagement with contact bar 4| to thereby interrupt the holding circuitof the coil 51 and with resultant deenergization of the heater 2|.

It is therefore evident that my improved allday water heating systemwill permit, of relatively simple and easy central station control forpredetermined and different durations of time in any suitable or desiredmanner to start out the daytime use of hot water with a tank which iseither full of hot water or almost so, depending, of course, upon thecondition in which it was at the time of start of continued energizationat about midnight, and during the rest of the daytime and into the earlyevening, my improved system ensures that a predetermined fractional partof the water content of the tank is hot.

While Fig. 1 of the drawing shows a remote control system operating onthe carrier current system, I may use a somewhat similar system which Ihere designate only as wired radio it being only necessary that theabove described results of energization and deenergization of thecontrol element 45 is effected.

I have shown another method of control of the control element 45 of myimproved water heating system as embodying a secondary distributionsystem which is shown as including an auxiliary manually operablecontrol switch ill in the power house 83, this switch being adapted toenergize and deenergize a distribution circuit illustrated generally asincluding conductors I I3 and 5 which are entirely separate from theother supply circuit distribution system as described above inconnection with Fig. 1 of the drawing. One terminal of coil 41 isconnected by a conductor I H with the conductor 5 and the other terminalof coil 41 by a conductor 9 to conductor H3. The coil 41 of the controlelement 45 is therefore adapted to be energized by the usual 60 cyclecurrent or its equivalent, as now provided on alternating currentdistribution systems.

When the operator closes switch I momentarily he will effect the sameresult as was described hereinbefore for the system of Fig. 1 of thedrawing, namely, an energization of the heater 2| in case the tankcontains less than a predetermined fractional part of hot water, and itis, of course, further evident that not only the system of Fig. 2 butalso in the system of Fig. 1 momentary closure of the switch I andmomentary energization of the control element 45 will not affectcontinuing energization of the heater 2| in case the upper thermalswitch 35 is responsive to the temperature of hot water.

In all other details the operation of the system shown in Fig. 2 of thedrawing is the same as that set forth in connection with the system ofFig. 1.

Referring now to Fig. 3 of the drawing, I have there shown anothersystem embodying my invention, in which the momentary and continuedenergization of the control system is effected by relatively simplemeans. I provide a manually actuable switch |2| in the central station83 here shown as a single pole knife blade switch having one terminalconnected to bus bar 9| and having its other terminal connected by aconductor |23 to conductor I25 in the control system at the hot watertank, the other end of conductor I25 being connected to conductor 66 andto one of the fixed contact members 83.

The switch |2| will operate in the same manher as does the controlelement 45, whereby momentary and continued closure of the switch |2|eifects energization of the heater 2| in the same manner as set forthabove for the control systems of Figs. 1 andZ.

Thesystems here disclosed and embodying my invention are thereforeeffective to start out the daytime with the tank practically or entirelyfull of hot water and further to maintain at least a predeterminedfractional part of the water content of the tank hot during the day, itbeing only necessary for the operator to manually momentarily close hiscontrol switch 31, ill or it! at spaced instants of time during the dayand. then to close this control switch at any desired time during theoff-peek period, which time will be as late as will ensure heating ofall the water in the tank before the end of the OE- peak period.. This,of course, is desirable since,

usually, the ofi-pesh period has a decided dip therein during some ofthe late night or early morning hours and it is, of course, ofimportance to the central station to fill out this valley in the curveto thereby maintain a higher efiiciency of current generation, all ashow well understood in the art.

Various other modifications may he made in the systems embodying myinvention without departing from the spirit or scope thereof and allsuch mcfiiilcetions clearly coming within the scope of the appendedclaims-ere to be considered as losing coverec thereby.

I claim as '3; ihventioilz l. A wet heating systei' ahot water tankhaving an electri heete' "11,-" a main -tch subject e levies pert inclosed of the and eels ted 'tc- "position until suTc-stent' lily 21water in the tent: is hot, 9. seconrl is, in series circuit relation toth upper pert ct the jointly effective with tliez switch. to causeclosure of s control switch and momentary ehc in case the the: i'eshcnsipreset-er velue. eating system-i for a hot water tank having hea er,conipris electrc magnet control switch, ti switch subject to t tasteran. inter-- mecilete l cczmected to contrcl ssici electrcmegheticswivels, a second heater control switch anti co'nnecticns lzetween saidheater and said switches to cease momentary closure l at secchcl heatercciitioi switch at atlme se switch is subject to cold; Water to Efifitenergizetioc of said heater through said electrcmeghetic switch untilseici thermal. switch is sucject to hot Water to cause continued closureseicl second heate control switc 1 when self. thermal switch i sulo=ject to hot water to effect eisergizetioh of ssicl heater through seiaisecond heater control switch clone untit suhstsntiellz. all of the waterin the tank is hot.

3. s. water heating system fez" e hot water tent; having an electricheeter, ccmhrising eh clectto= magnetic heater control switch, ttellyresponsive switch 1 cstetl sgirecietermined upper part of the tent,emi held in clcsecl pcsi tion when its ambient we e2" temperetcre isbelow a certein value, a secomi hetic switch the contests clwhich wecehheccecl shunt circuit relation to these cf cameo clec tromegneticswitch, mecrzc controlling the gizetion oi selici first electtomesnetlcswitch and. electric connections between seizi switches Whfil'fi bymomehtety energizction iii the first clecttc msgnetic switch at s, timewhen the ambient Welter temperature of the tlieimellg respchsivc swimhis below seiol certain value senses clcsm'e cf scald ascend hsmecielccti'cmccnetic switch and of selzi switches, momentary energisetioh ctenergization of the heater until the ambient water temperature of thethermally-responsive switch is above said certain value.

4. A water heating system for a. hot water tank having an electrichltt/EI', comprising an electromagnetic heater control switch, sthermallyresponsive switch located at a. predetermined upper pert of thetank and held in closecl position when its ambient water temperature isbelow a certain value, a, second electromagnetic switch the contacts ofwhich are connected in shunt circuit relation to those of said firstnamed electromegnetic switch, remotely, locetecl means controlling theenergizetion of said first electro magnetic switch and electricconnections between said switches whereby energizetion of ssicl remotelylocetecl control means to cause continuing closure of said firstelectromagnetic switch efiects continuing ehersizction of scicl heaterii'resgcec-, tive ot" the em'cient water *emttemture attesting saidthermally-responsive switch.

5. The method of maintaining pretietermined quantity of hot water intank subject to drewels of venting quantities of hot from at l-lifieeenttimes of the clay, which comprise mcmentesy energizetion cl 2', controlsystem for ciesitetimes of clay tc cause e'nergizetioh ti'ic heater forthe case the ts less them said. rmlhecl client-i water continua ticnuntil the mined quantity or es contain self. predic oi; water. systemfor e hot J. Etc

i3, heater-energizing scicl cchtrcl means responsive to com tlnueccncmizetioii or? seicl control mcem tc ceuse energize-the oi the heetei"encl continuance of energizetioh vhtil substantially all of teeter inthe tent: is hot and en auxiliary ones sizing circumt respczisive tomomentary Gi glz-stioh cf ssicl control means to cause encr tlon of theer in case the tech is less epprosimetely hell full of hot wet-es, sciclelection continuinc until the tent; is commit mctely hslf full oi hct 7.A system es claimed in claim t and including a second thermally sctuebleswitch electrical ly connected in series circuit releticn with firstncmei electromagnetic heater cohtiol switch, eflective to causecleenergizetion of the electric heater when substantially all of thewater in the tank m hot.

8. A water hestlrzg system for e hct water having an electric heeter,comprising eiec tromsgnetic switch, an auxiliary electronics-metricswitch electitcellt ccvziecteei in sheet with first hemezielectrcmceiictic cwitc a meih their malls ectueble switch so pcsiticnedin the tech that it is moved. open position when substatitielly all of;the wet-er i he tech is hot, secoml thermally ectuchle cw uch sopcsitloiiecl in tank that it is moved to open pe ition when atpredetermined c past of the wstes iii the tank is het, eiec i occmiectiohs hett'vesc eil first electromagnetic e itch ceusing-cnescizction of the heater through said sccchcl electto magnetic switch saidmain tl'lemzclly cots. able switch amt-ii ssbstcntielly seiclpi'eciete'r mined fractional pert oi the teeter in the is hot andcontinued Eilelg12til1 ci electromagnetic eheicissttcn the heaterthrough said first electromagnetic switch and said main thermallyactuable switch until substantially all of the water in the tank is hot.

9. A water heating system for a hot water. tank having an electricheater,comprising a main and an auxiliary thermal switch subject to tankwater temperature at different heights of the tank, an electromagneticheater control switch, a fourth switch and electric circuit connectionsbetween the heater and all of said switches to cause momentary closureof said fourth switch to efl'ect continuing energization of the heaterthrough the electromagnetic switch and the main thermal switch in caseless than a predetermined fractional part of the water content of thetank is hot at the time of said momentary closure of said fourth switchand to cause continued closure of said fourth switch to effectenergization of the heater through the main thermal switch only.

10. The method of maintaining different predetermined quantities of hotwater in a tank subject to withdrawals of varying quantities of hotwater therefrom at 'diflerent times of day, said tankhaving an electricheater and a control system for said heater, said method comprising thestep of momentarily energizing the heater control system at differentspaced times of day to cause energization of the electric heater in caseless than a predetermined fractional part of the water content of the ishot and the step of continuously energizing the heater control system atanother part of day to cause energization of the electric heater in caseless than all of the water content of the tank is hot.

11. A water heating system for a hot water tank having an electricheater and subject to withdrawals of hot water therefrom at diiferenttimes during a twenty-four hour day, comprising a main thermal heatercontrol switch adapted to cause deenergization of the heater whensubstantially all of the water in the tank is hot, an auxiliary thermalswitch responsive to tank water temperature at an intermediate point ofthe tank, an electromagnetic heater control switch, remotely energizablecontrol means for said electromagnetic switch, a second electromagneticheater control switch and electric connections between said switches andthe heater to tend to maintain in a heated condition a predeterminedfractional part of the water content of the tank dun'ng a predeterminedpart of a twenty-four hour day by energization of the heater through acircuit including the second electromagnetic switch and the main thermalswitch, and to tend to maintain in a heated condition all of the watercontent of the tank during another part of a twenty-four hour day byenergization of the heater through a circuit including said first namedelectromagnetic switch and said main thermal switch.

CLARK M. OSTERHELD.

